The present invention relates generally to devices used to sequentially process sheet material articles, and in particular to a registration apparatus for a sheet material article handler.
Apparatus which handle sheet material articles include trimmers and printers. In such apparatus, registration of the sheet material articles is performed before a trimming or printing operation, for example. Backstops which move in and out of the path of the sheet material articles may be used to perform the registration function.
In a known apparatus for trimming sheet material articles, such as books, a front knife assembly trims front edge portions of the books. A shuttle pushes each of the books in turn onto the moving front knife table of the apparatus. As the book moves onto the moving table, a leading edge or back of the book engages backstops which register the book relative to the front knife. After the front knife trimming operation, the backstops retract out of the path of the book so that the book may be moved onto the side knife assembly. The backstops travel in a substantially vertical motion in and out of the path of the book as it travels through the trimmer. The backstops travel from below the book path up into the book path, and then back down out of the book path.
The cycle time of the backstops to get into and out of position limits the speed at which books can move through the trimmer. The up-motion of the backstops cannot start until the entire book has cleared the backstops location. Similarly, the book cannot move past the backstop location until the backstops are completely down and out of the book path.
The above-described known apparatus for trimming books or other sheet material articles is disclosed in U.S. Pat. No. 3,733,947 issued May 22, 1973 and entitled “Book Trimming Machine”. An apparatus for trimming books and other sheet material articles and constructed as disclosed in this patent has been commercially available from Harris Graphics, a division of AM International, of 4900 Webster Street, Dayton, Ohio 45414 and is referred to as the HT-15 Trimmer.